In many areas, efforts are currently underway to transition the world's energy consumption from fossil fuels to renewable energy sources. Because today's electric grid is in part powered by non-renewable energy sources, the transition effort has in part focused on facilitating generation and storage of energy locally, instead of at remote power plants. This can involve solar power (i.e., photovoltaic panels that convert sunlight into electricity) or wind power (i.e., wind turbines at a wind farm). Because the output of these types of energy sources fluctuates during the day, and because the demand for energy does as well, the ability to store electric energy for later use becomes important.
One of the key technologies for storing electric energy is electrochemical cells (e.g., lithium-ion cells). Their advantages are well known: they have high energy density, can deliver significant power when necessary, and can be reused many times. Like most types of energy storage, electrochemical cells must be operated properly so as to give optimum performance and not malfunction. Such operation involves controlling the charging and discharging processes, as well as managing the temperature of the cells. In extreme situations, a cell that is malfunctioning can undergo a process called thermal runaway in which the cell generates excessive heat. Eventually the thermal runaway cell can begin emitting smoke and jets of electrolyte from its housing. This can affect nearby cells as well as other equipment.